How prehistoric humans have survived a supervolcana so large that we should probably have disappeared

If you were lucky 74,000 years ago, you would have survived Toba’s super-rection, one of the biggest catastrophic events that the land has seen in the 2.5 million years.

While the volcano is located in what is now in Indonesia, organisms living in everyone have been potentially affected. As aarchologist specializing in the study of volcanic eruptions of the past, I often think of the way in which it is incredible that humans have survived this event at the level of extinction which was more than 10,000 times larger than the eruption of Mount St. Helens of 1980.

The Toba super-ulucation ejected 672 cubic miles (2,800 km³) of volcanic ash in the stratosphere, producing a huge crater of around 1,000 football fields (62 x 18 miles or 100 x 30 kilometers). An eruption of this size would have produced a dark sky blocking most of the sunlight, potentially causing years of global cooling. Closer to the volcano, the acid rains would have contaminated water supplies and thick ash layers would have buried animals and vegetation.

With all these stacked chances Homo sapiens As a species, how did we survive to reconstruct history today?

Survival in the middle of ashes

The human populations living near the Toba volcano have probably been completely wiped out. The question of whether people in other parts of the globe have been affected is a question that scientists are still in surveillance.

The hypothesis of Toba’s disaster was an eminent school of thought for many years. He suggests that Toba’s super-utility has caused a global cooling event that lasted up to six years. According to the hypothesis, its effects have dropped human population sizes to less than 10,000 individual people living on earth.

This scenario is supported by genetic evidence found in the genomes of living people today. Our DNA suggests that modern humans have spread in separate regions about 100,000 years ago, then shortly after that, which scientists call a bottleneck of genetic strangulation: an event, like a natural disaster or an epidemic of illness, which leads to a sharp drop in the size of the population. These calamities considerably reduce genetic diversity in a group.

Whether this apparent reduction in the size of the human population results from Toba’s super-rection or another factor is strongly debated. While scientists collect more data from climatic, environmental and archaeological files, we can start understanding what conditions were most important for human survival.

How to study the impact of a cum

To reconstruct what happened 74,000 years ago, scientists have a direct line of evidence that they can use: rock and ejected ash of the volcanic eruption itself. This material is called Téphra. Scientists can trace the layers of Téphra through the visually and chemically landscape.

The microscopic volcanic glass called Cryptotephra travels the furthest, which makes it important to understand the real extent of an eruption. Because cryptotphra is not visible to the naked eye, it can be really difficult to identify. Researchers like me carefully separate small glass shards by passing through dirt and using a micro -manipulator, a tool that can pick up and move microscopic grains. This process may have the impression of looking for a needle in a haystack and can take months to finish for a site.

Each volcanic eruption has a single chemistry, which scientists can use to determine what eruption a particular sample of volcanic material comes. For example, the Téphra of an eruption could be more iron compared to TEPHRA from another eruption. With this knowledge, we can start understanding how important the eruptions were and which they affected directly.

When I work in the field, I am looking for a cryptotephra that has settled on archaeological sites – places with traces of past human activity such as tools, art or even buried remains. I collect samples in areas of the site that have been excavated and bring them back to the laboratory to extract microscopic volcanic glass out of dirt. Then, I chemically analyze glass to understand the volcanic fingerprint.

But even if I determine that a certain sample of an archaeological site comes from Toba’s super-use, what does it reveal if people have survived the explosion?

Once we have identified a layer of Téphra or Cryptotephra, the next step is to closely examine what is kept in the archaeological file before and after this eruption. In some cases, people change behavior after an eruption, such as using a new technology of stone tools or eating something different. Sometimes people even abandon a site, leaving no trace of human activity after a catastrophic event.

However, the study of volcanic deposits on archaeological sites fulfills only one piece of the puzzle. Environmental and climatic files preserve information on how local vegetation or global temperatures have changed at the time of the eruption. This information helps scientists understand why people have made the changes they have made.

What does archaeological evidence reveal?

Given the size and intensity of Toba’s super-rection, it seems almost inevitable that humans around the world would have suffered enormously. However, most archaeological sites tell a story of resilience.

In places like South Africa, humans have not only survived this catastrophic event but prospered. At the archaeological site Pinnacle point 5-6, evidence of Cryptotephra de Toba show that humans occupied the site before, during and after the eruption. In fact, human activity has increased and new technological innovations appeared shortly after, demonstrating the adaptability of humans.

This miraculous result was not limited to South Africa. Similar evidence is also preserved on the Shinfa-Metème 1 archaeological site in the plains of Ethiopia, where Toba Cryptotephra was present in layers which also preserve human activity.

Here, the ancient humans have adapted to changes in the local environment by following the seasonal rivers and fishing in small shallow water holes present during the long dry seasons. At the time of Toba’s super-rection, humans in this region also adopted the technology of arcs and arrows. This behavioral flexibility allowed people to survive intense arid conditions and other potential effects of Toba’s super-use.

Over the years, archaeologists have found similar results on many other sites in Indonesia, India and China. As the evidence accumulates, it seems that people have been able to survive and continue to be productive after Toba blew up his battery. This suggests that this eruption was perhaps not the main cause of the population of the population initially suggested in the event of Toba’s disaster.

Although Toba may not help scientists understand what caused the fall of old human populations to 10,000 individuals, this helps us to understand how humans have adapted to catastrophic events in the past and what it means for our future.

What could a future disaster mean?

The good news is that we are much more prepared now than people were not 74,000 years ago, and even then, they were able to adapt and find new solutions following devastating events. Today, programs such as the USGS volcanic risk program and the global volcanism program focus on preparation by monitoring active volcanoes thanks to a variety of techniques. In fact, you can check which volcanoes are currently exploding at any time.

Aside from our increased preparation, humans are defined by our adaptability to almost all conditions, even cataclysmic events. By studying the impact of volcanic eruptions in archaeological archives, we can better understand what conditions were essential for human survival in the past and apply these lessons in the future.

Jayde N. Hirniak, Ph.D. candidate in anthropology, Institute of human origins, Arizona State University. This article is republished from the conversation under a Creative Commons license. Read the original article.